Composite cathode material, preparation method thereof, cathode sheet, solid-state battery and electric device

Abstract

The application relates to the secondary battery technical field, discloses a kind of composite positive electrode material and its preparation method and positive pole piece, solid battery and electric equipment.The composite positive electrode material includes core and cladding shell, the core includes positive electrode active material, the cladding shell includes sulfide, the molecular formula of the sulfide is Li a Ti b Ge c P x S y X z , 0 X is selected from at least one of Te, Se and O.The application effectively constructs continuous ion / electron transmission channel by cladding sulfide shell with specific composition on the surface of positive electrode active material, reduces the number of hetero-interface, avoids the addition of non-active substance, increases the proportion of active substance in electrode, improves the energy density of battery, and reduces internal resistance and enhances the rate performance.

Description

Technical Field

[0001] This application relates to the field of secondary battery technology, and in particular to a composite cathode material and its preparation method, as well as cathode sheets, solid-state batteries and electrical devices. Background Technology

[0002] With the increasing demands for battery energy density and safety in the energy sector, solid-state batteries, with their high energy density and intrinsic safety, are considered a key direction for future battery technology development. Among all-solid-state battery technologies, sulfide systems exhibit significant application potential due to their high ionic conductivity, low Young's modulus, and wide electrochemical window. However, existing sulfide solid-state batteries still face many challenges in practical applications, particularly in the cathode region.

[0003] First, the limited ion and electron transport capabilities of positive electrode active materials necessitate the introduction of large amounts of electrolyte or conductive carbon to improve conductivity during the construction of solid-state positive electrode composites. This reduces the content of active material in the electrode, thereby lowering the overall energy density of the battery. Second, solid-state positive electrode composites typically consist of multiple components, increasing the number of heterojunctions. This makes the ion and electron transport paths more tortuous, significantly increasing the internal resistance and severely limiting the battery's rate performance. Furthermore, during charge and discharge, inconsistent volume changes in different components can easily lead to interfacial stress concentration, resulting in poor interfacial contact and a continuous increase in resistance, further deteriorating the battery's rate capability.

[0004] To address the aforementioned issues, patent WO2025150927A1 proposes a double-layer electrolyte coating structure. By setting an electrolyte layer in a specific ratio on the surface of the positive electrode active material, combined with coating and heat treatment processes, it alleviates interfacial impedance and ion conduction problems to some extent. However, this solution still requires adding a high proportion of electrolyte inside the electrode, leading to a decrease in energy density, and it fails to effectively solve the heterogeneous interface problem between multiple components. Patent US20170317382A1 uses a single solid electrolyte material to construct the electrode and electrolyte layer, and adds a carbon conductive agent, achieving an integrated design of the electrode and electrolyte and reducing interfacial resistance. However, this technology mainly focuses on interface optimization between electrode layers, lacking effective measures to address the interface stability problem within the electrode layer. Therefore, existing technologies still have significant shortcomings in improving the performance of solid-state battery positive electrodes. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a composite cathode material and a method for preparing the same, such that the composite cathode material can significantly improve the energy density and ion / electron conduction performance of the cathode electrode, and can also reduce interfacial impedance and improve the rate performance of solid-state batteries.

[0006] Another object of this application is to provide a positive electrode, a secondary battery, and an electrical device based on the binder described in this application.

[0007] To achieve all or part of the above objectives, as a first aspect of this application, a composite cathode material is provided, comprising a core and a coating shell, wherein the core comprises a cathode active material, and the coating shell comprises one or more sulfides with the molecular formula Li. a Ti b Ge c P x S y X z , 0<a≤4, 0≤b≤4, 0≤c≤3, 0≤x≤3, x+c=3; 0≤y≤12, 0≤z≤12, y+z=12; X is selected from at least one of Te, Se, and O.

[0008] Optionally, the mass ratio of the positive electrode active material to the sulfide is 80:20-99.95:0.05. More preferably, the mass ratio of the positive electrode active material to the sulfide is 90:10-99.5:0.5. Even more preferably, the mass ratio of the positive electrode active material to the sulfide is 97:3-99:1.

[0009] Optionally, the positive electrode active material includes lithium iron phosphate; lithium manganese iron phosphate; lithium-rich manganese-based active material; LiCoO2; LiNiO2; LiMnO2; Li2MnO3; LiMn2O4; LiNi a Co b Mn c O2, where 0 <a<1,0<b<1,0<c<1,a+b+c=1;LiNi 1-y Co y O2, where 0 <y<1;LiCo 1-y Mn y O2, where 0 <y<1;LiNi 1-y Mn y O2, where 0 <y<1;LiNi a Co b Mn c O4, 0 <a<2,0<b<2,0<c<2,a+b+c=2;LiMn 2-z Ni z O4(0 <z<2);LiMn 2-z Co z O4, where 0 <z<2;LiNi x Al y Co zO2, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1; sodium-ion layered oxide; sodium-ion Prussian blue; sodium-ion polyanion and one or more combinations of their modified dopants.

[0010] Optionally, the sulfide has the molecular formula Li 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Se 0.2 )3, Li 1.75 Ti2(Ge 0.3 P 0.7 S 3.8 Se 0.2 )3, Li 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Te 0.2 )3 or more than one of them.

[0011] Optionally, the number of layers of the coating shell is 1 - 10 layers.

[0012] As the second aspect of the present application, a preparation method of the composite cathode material as described in the present application is provided, including: Taking raw materials containing Li, Ti, Ge, P, S, and X according to the atomic ratio, fully mixing them in a protective gas atmosphere, then adding supplementary S and annealing at 300 - 800 °C for 4 - 12 h to obtain a sulfide with the molecular formula Li a Ti b Ge c P x S y X z ; Fully mixing the cathode active material with the sulfide and calcining at 100 - 350 °C for 0.5 - 3 h to obtain the composite cathode material.

[0013] Optionally, the raw materials containing Li, Ti, Ge, P, S, and X include one or more of S, Li2S, P2S5, TiS2, GeS2, and TiX2.

[0014] As the third aspect of the present application, a cathode electrode sheet is provided, including a current collector and a cathode electrode layer provided on at least one surface of the current collector; the cathode electrode layer includes the composite cathode material as described in the present application and a binder.

[0015] Optionally, the mass percentage of the composite cathode material is 95 - 100%.

[0016] As a fourth aspect of this application, a solid-state battery is provided, including the positive electrode sheet described in this application, as well as a negative electrode sheet and a solid electrolyte.

[0017] As a fifth aspect of this application, an electrical device is provided, including the solid-state battery described in this application, wherein the solid-state battery provides electrical energy to the electrical device or serves as an energy storage unit for the electrical device.

[0018] This application effectively constructs a continuous ion / electron transport channel by coating the surface of the positive electrode active material with a sulfide shell of a specific composition. This reduces the number of heterojunctions and avoids the addition of inactive materials, increases the proportion of active materials in the electrode, improves the battery energy density, and reduces internal resistance to improve rate performance. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. Figure 1 The image shown is a SEM image of the LTGPSSe-1 cathode composite material prepared in Example 1 of this application; Figure 2 The image shown is a TEM image of the LTGPSSe-1 cathode composite material prepared in Example 1 of this application. Detailed Implementation

[0020] This application discloses a composite cathode material and its preparation method, as well as a cathode electrode, solid-state battery, and electrical device. Those skilled in the art can refer to the content of this application and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this application. The products and processes described in this application have been described through preferred embodiments. Those skilled in the art can obviously modify or appropriately change and combine the products and processes described herein without departing from the content, spirit, and scope of this application to realize and apply the technology of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0021] It should be noted that, in this document, relational terms such as "first" and "second," "step 1" and "step 2," and "(1)" and "(2)" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Moreover, the embodiments and features described in this application can be combined with each other without conflict.

[0022] In traditional solid-state battery technology, the limited ion and electron transport capabilities of the positive electrode active material necessitate the addition of excessive electrolyte materials or conductive agents to the composite electrode structure to maintain electrochemical performance, thereby reducing the battery's energy density. Simultaneously, the multi-component structure within the composite electrode increases the proportion of heterojunctions, amplifying the tortuosity of ion and electron conductance, leading to increased internal resistance and impacting rate performance. Furthermore, during charge and discharge, inconsistent volume changes in different components cause interfacial instability and increased resistance, further reducing rate performance. Specifically, the increased number of heterojunctions elongates the ion transport path and reduces electron conduction efficiency, while volume mismatch leads to interfacial stress accumulation, exacerbating the deterioration of interfacial impedance.

[0023] Based on this, in the first aspect of this application, a composite cathode material is provided, comprising a core and a coating shell, wherein the core comprises a cathode active material, and the coating shell comprises one or more sulfides with the molecular formula Li. a Ti b Ge c P x S y X z , 0<a≤4, 0≤b≤4, 0≤c≤3, 0≤x≤3, x+c=3; 0≤y≤12, 0≤z≤12, y+z=12; X is selected from at least one of Te, Se, and O, for example, X can be Te, Se or O; it can also be Te and O, or Se and O, or Te and Se; it can also be Te, Se and O.

[0024] Where 'a' can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2. 75, 2.8, 2.85, 2.9, 2.95, 3, 3.05, 3.1, 3.15, 3.2, 3.25, 3.3, 3.35, 3.4, 3.45, 3.5, 3.55, 3.6, 3.65, 3.7, 3.75, 3.8, 3.85, 3.9, 3.95, 4, or any value between any two; b can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3. 2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, or any value between any two; c can be 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2.75, 2.8, 2.85, 2.9, 2.95, 3, or any value between any two; x can be 0, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2.75, 2.8, 2.85, 2.9, 2.95, 3, or any value between any two; y can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3 7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10. 2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12, or any point value between any two; z can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3. 8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12, or any value between any two of these.

[0025] The composite cathode material of this application can be prepared in various ways. For example, it can be prepared by co-precipitating cathode active material particles with a sulfide precursor, followed by heat treatment to form a uniform coating layer on the surface of the active material. Another method is to mechanically mix cathode active material powder with pre-synthesized sulfide powder, and then form a composite material through compaction or sintering. Spray drying technology can also be used, where cathode active material slurry and sulfide slurry are mixed and then spray-dried to obtain composite particles with a core-shell structure.

[0026] The core, as the central component of the composite cathode material, primarily functions to provide active sites for electrochemical reactions. The core can be composed of various types of cathode active materials. For example, layered oxide materials with high energy density, such as lithium cobalt oxide or lithium nickel manganese cobalt oxide, can be selected. Olivine-type materials with good cycle stability, such as lithium iron phosphate, can also be used. Furthermore, spinel-type materials, such as lithium manganese oxide, can be employed, which exhibits excellent rate performance.

[0027] The coating shell comprises one or more sulfides. This sulfide layer directly covers the surface of the positive electrode active material, aiming to improve the interfacial properties between the active material and the electrolyte. For example, the coating shell can be composed of only one sulfide material to simplify the material system. Alternatively, it can be composed of a combination of two or more different types of sulfide materials to optimize the overall performance of the coating layer through synergistic effects, such as simultaneously improving ionic / electron conductivity and mechanical stability.

[0028] In this application, the sulfide Li a Ti b Ge c P x S y X z It has the following performance characteristics: (1) It has high electron conductivity, with an electronic conductivity of ≥100 ms / cm at room temperature; (2) It has high ion conductivity, with an ion conductivity of ≥0.1 ms / cm at room temperature; (3) It has electrochemical activity for lithium ion insertion and extraction, with a specific capacity ≥170mAh / g; (4) The volume change during the charging and discharging process is extremely small (<1.2%), which is equivalent to a zero-strain material; The sulfide used to coat the outer shell has a specific molecular formula Li.a Ti b Ge c P x S y X z The atomic stoichiometry coefficients a, b, c, x, y, and z of lithium (Li), titanium (Ti), germanium (Ge), phosphorus (P), sulfur (S), and element X are controlled within specific ranges. For example, the lithium-ion transport capability of the sulfide can be optimized by adjusting the lithium content a to be within the range of 0 < a ≤ 4. The titanium content b can be varied within the range of 0 ≤ b ≤ 4 to affect the structural stability of the sulfide. The germanium and phosphorus contents c and x, within the ranges of 0 ≤ c ≤ 3 and 0 ≤ x ≤ 3, and satisfying the condition x + c = 3, can jointly construct the framework structure of the sulfide, affecting its crystal phase and ion diffusion pathway. The sulfur and element X contents y and z, within the ranges of 0 ≤ y ≤ 12 and 0 ≤ z ≤ 12, and satisfying the condition y + z = 12, can adjust the anionic sublattice of the sulfide, thereby affecting its electrochemical window and interfacial compatibility. Element X can be selected from one or more of tellurium (Te), selenium (Se), and oxygen (O). For example, selecting selenium as element X can further optimize the lattice parameters of sulfides and enhance their structural stability during charging and discharging.

[0029] The composite cathode material of this application, through its core-shell structure design, effectively solves the problems of limited ion and electron transport capabilities of the cathode active material in solid-state batteries, increased internal resistance due to excessive heterogeneous interface ratio within the composite electrode, and interface instability caused by inconsistent volume changes during charge and discharge. Therefore, without sacrificing energy density, it improves the ion and electron transport efficiency of solid-state batteries, reduces interface impedance, and enhances interface stability. It exhibits electrochemical activity for lithium-ion insertion and extraction, and has a high specific capacity, thus providing a key material foundation for realizing high-performance all-solid-state batteries.

[0030] In some embodiments of this application, the mass ratio of the positive electrode active material to the sulfide is 80:20-99.9:0.1. By precisely controlling the mass ratio of the positive electrode active material to the sulfide within the range of 80:20 to 99.95:0.05, the sulfide coating can be uniformly distributed on the surface of the positive electrode active material core with appropriate thickness and coverage. This specific ratio setting ensures that the sulfide coating layer can effectively improve interface performance while maintaining a high loading of the positive electrode active material. Specifically, when the sulfide content is within this optimized range, it can form a continuous and dense coating layer, effectively reducing the interfacial impedance between the positive electrode active material and the solid electrolyte, promoting rapid lithium-ion transport at the interface, while avoiding excessive dilution of the energy density of the positive electrode active material due to an excessively high sulfide content. In addition, an appropriate amount of sulfide coating can help alleviate the volume change of the positive electrode active material during charging and discharging, thereby maintaining the stability of the interface, reducing the internal resistance of ion and electron transport caused by the increase of heterogeneous interfaces, and thus improving the rate performance of the composite positive electrode material.

[0031] In other embodiments of this application, the mass ratio of the positive electrode active material to the sulfide is 90:10-99.5:0.5, for example, 90:10, 90.5:9.5, 91:9, 91.5:8.5, 92:8, 92.5:7.5, 93:7, 93.5:6.5, 94:6, 94.5:5.5, 95:5, 95.5:4.5, 96:4, 96.5:3.5, 97:3, 97.5:2.5, 98:2, 98.5:1.5, 99:1, 99.5:0.5, or any value between the two. By further limiting the mass ratio of the positive electrode active material to the sulfide within the range of 90:10-99.5:0.5, fine control of the component ratio of the composite positive electrode material is achieved. In the aforementioned composite cathode material, the active cathode material forms the core, while sulfides form the outer shell. When the mass percentage of sulfides is low (0.5% to 10%), a thin and uniform coating layer is formed on the surface of the active cathode material, avoiding the problem of reduced overall energy density due to excessive sulfide content. Simultaneously, this precise ratio control allows the sulfide coating layer to effectively provide ion / electron transport channels and stabilize the interface between the active cathode material and the electrolyte. This maintains efficient ion / electron transport while reducing the increase in internal resistance caused by excessive heterogeneous interfaces of multiple components. Compared to a wider mass ratio range, this approach, through stricter ratio control, allows the sulfide coating layer to function more effectively, optimizing interface characteristics and ion / electron transport efficiency without significantly sacrificing energy density.

[0032] In some other embodiments of the present application, the mass ratio of the positive electrode active material to the sulfide is 97:3 - 99:1, such as 97:3, 98:2, 99:1 or any value between any two of them; by optimizing the mass ratio of the positive electrode active material to the sulfide within the range of 97:3 - 99:1, a coating layer with an appropriate thickness and uniformity can be formed on the surface of the positive electrode active material by the sulfide, so as to exchange the lowest coating amount that hardly affects the energy density for the maximization of interface stability. This can avoid the extra interfaces introduced due to the too thick coating layer to the greatest extent, instead increasing the internal resistance of the battery, so as to maintain an efficient ion / electron transport channel while ensuring mechanical stability.

[0033] In some embodiments of the present application, the positive electrode active material includes lithium iron phosphate (LFP); lithium iron manganese phosphate (LFMP); lithium-rich manganese-based active material; LiCoO2; LiNiO2; LiMnO2; Li2MnO3; LiMn2O4; LiNi a Co b Mn c O2, where 0 < a < 1, 0 < b < 1, 0 < c < 1, and a + b + c = 1; LiNi 1-y Co y O2, where 0 < y < 1; LiCo 1-y Mn y O2, where 0 < y < 1; LiNi 1- y Mn y O2, where 0 < y < 1; LiNi a Co b Mn c O4, 0 < a < 2, 0 < b < 2, 0 < c < 2, and a + b + c = 2; LiMn 2-z Ni z O4(0 < z < 2); LiMn 2-z Co[[ID=…]] z O4, where 0 < z < 2; LiNi x Al y Co z O2, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1; sodium-based layered oxide; sodium-based Prussian blue; sodium-based polyanion and one or more combinations of their modified dopants.

[0034] The positive electrode active materials defined in this application encompass a variety of material systems with different crystal structures and electrochemical properties, aiming to ensure good interfacial compatibility with the sulfide coating layer. Among them, LFP and LFMP are polyanionic positive electrode materials, characterized by structural stability, high thermal stability, and a stable voltage plateau, providing good safety performance and cycle life for the battery. Lithium-rich manganese-based active materials, with their high specific capacity, have significant potential for improving battery energy density. LiCoO2, LiNiO2, LiMnO2, and various multi-layered oxides (such as LiNiO2, LiNiO2, and LiNiO2) are also included. a Co b Mn c O2, LiNi 1-y Co y O2, LiCo 1-y Mn y O2, LiNi 1-y Mn y O2, LiNi x Al y Co z O2, etc., represent layered oxide systems. These materials typically possess high energy density and operating voltage, making them the mainstream cathode materials for lithium-ion batteries. Li2MnO3, LiMn2O4, and their derivatives (such as LiMn...) 2-z Ni z O4, LiMn 2-z Co z O4, LiNi a Co b Mn c O4) belongs to spinel-type or lithium-rich manganese-based materials. Spinel-structured materials typically possess excellent rate performance and three-dimensional ion transport channels. Furthermore, the introduction of sodium-electric layered oxides, sodium-electric Prussian blue, and sodium-electric polyanions, among other sodium-electric related materials, expands the application of this composite cathode material in sodium-ion battery systems, demonstrating its versatility in different ion-carrier batteries. Modification and doping refer to the introduction of small amounts of other elements into the above-mentioned cathode active materials for doping or surface modification, in order to further optimize their crystal structure, improve ionic / electronic conductivity, enhance interfacial stability, or suppress side reactions, thereby improving the overall electrochemical performance of the material.

[0035] In some embodiments of this application, the sulfide has the molecular formula Li. 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Se 0.2 3. Li 1.75 Ti2(Ge 0.3 P 0.7 S 3.8 Se0.2 3. Li 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Te 0.2 One or more of the following 3. These specific sulfide chemical compositions are optimized to serve as the coating shell for composite cathode materials, providing excellent interfacial protection and ion / electron transport performance. In particular, the precise ratio of lithium, titanium, germanium, phosphorus, sulfur, and selenium is determined based on the adaptation of the material's electrochemical window, ionic conductivity, and interfacial compatibility with the cathode active material. By introducing specific proportions of selenium or tellurium, the band structure and ion transport channels of the material can be effectively adjusted, thereby ensuring high ion / electron conductivity while improving the chemical stability of the coating layer during charge and discharge, and giving it the electrochemical activity of lithium-ion insertion and extraction, thus increasing the specific capacity.

[0036] In some embodiments of this application, the number of layers of the coating shell is 1-10, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 layers, etc.; the number of layers of the coating shell refers to the number of physical layers of the sulfide coating shell formed around the positive electrode active material. This number of layers limits the spatial complexity and functional controllability of the coating structure. For example, the coating shell can consist of only one layer of sulfide, directly covering the surface of the positive electrode active material to form a single interface protective layer. Alternatively, the coating shell can be composed of multiple layers of sulfide stacked together, such as two, three, or even ten layers, with each layer having different composition, density, or structural characteristics, thereby forming a gradient or composite interface structure. This multi-layer design allows for fine-tuning of interface performance to adapt to the complex volume changes and electrochemical reaction requirements of the positive electrode active material during charging and discharging.

[0037] In a second aspect of this application, a method for preparing a composite cathode material is provided, which optimizes the interface structure by stepwise synthesis of a specific sulfide and uniform coating of it on the surface of the cathode active material.

[0038] First, raw materials containing Li, Ti, Ge, P, S, and X are thoroughly mixed in a protective gas atmosphere according to their atomic ratio. Then, supplementary S is added, and the mixture is annealed at 300-800℃ for 4-12 hours to obtain a product with the molecular formula Li. a Ti b Ge c P x S y X zThe sulfide; wherein the description and description of the sulfide molecular formula can be found in the description and description of the first aspect of this application; the addition of supplementary S can effectively compensate for the volatilization loss of sulfur during high-temperature annealing, ensuring the integrity of the sulfide crystal structure and high ionic conductivity, and the molar amount of supplementary S is equal to the amount of Li synthesized. a Ti b Ge c P x S y X z The molar amount is 0-20%, for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value between the two; Then, the positive electrode active material is thoroughly mixed with the sulfide and calcined at 100-350°C for 0.5-3 hours to obtain the composite positive electrode material.

[0039] In some embodiments of this application, the annealing temperature can be selected from 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, or any value between the two; the annealing time can be selected from 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, or any value between the two. The selection of suitable high-temperature annealing temperature and time in this application can better meet the thermodynamic and kinetic requirements simultaneously: it can provide sufficient energy to promote the complete reaction of the precursor, form a highly crystalline pure target phase and suppress the formation of harmful impurity phases, and avoid excessive temperature or time leading to loss of sulfur and volatile components, excessive grain growth or irreversible phase transformation, thereby ensuring that the sulfides of this application obtain high ionic / electronic conductivity, stable microstructure and accurate stoichiometry.

[0040] In some embodiments of this application, the raw materials containing Li, Ti, Ge, P, S, and X include one or more of S, Li₂S, P₂S₅, TiS₂, GeS₂, and TiX₂. Li₂S and P₂S₅, as core components of the sulfide electrolyte system, provide a stable lithium-ion conduction framework and abundant lithium-ion carriers, forming the basis for efficient lithium-ion transport in the sulfide coating. Simultaneously, the added S, as a supplementary sulfur source, can precisely adjust the stoichiometry of the sulfide, ensuring sufficient reaction during annealing to form a well-structured crystal with few defects. Furthermore, TiS₂, GeS₂, and TiX₂, as doping or substitution components, can finely control the crystal structure, band structure, and electrochemical window of the sulfide by introducing different metal or non-metal elements, optimizing the lithium-ion transport path and improving the air stability or electrochemical stability of the sulfide. These raw materials, after thorough mixing and annealing in a protective gas atmosphere, can efficiently form Li₂ with a specific molecular formula. a Ti b Ge c P x S y X z The sulfide has excellent ionic / electronic conductivity, and its structure and composition have been optimized to form a good interface with the positive electrode active material, reduce interface impedance, and improve the transport efficiency of lithium ions inside the positive electrode.

[0041] In some embodiments of this application, the protective gas includes, but is not limited to, nitrogen and inert gases, such as argon. The protective gas atmosphere is used to isolate oxygen and moisture from the air. Sulfides readily react with oxygen at high temperatures to form poorly conductive oxide impurities (such as Li₂O, P₂O₅, etc.), and also undergo hydrolysis with water vapor to release highly toxic H₂S gas, leading to electrolyte structure damage and loss of lithium-ion transport channels. Furthermore, the inert atmosphere can suppress the high-temperature volatilization of sulfur, maintaining an accurate stoichiometric ratio.

[0042] In a third aspect of this application, a positive electrode sheet is proposed, comprising a current collector and a positive electrode layer disposed on at least one surface of the current collector; the positive electrode layer comprises a composite positive electrode material and a binder. By combining the positive electrode active material as the core with a sulfide coating shell of a specific molecular formula in a core-shell structure, a tight interfacial contact is constructed inside the positive electrode, reducing the internal resistance of ion and electron transport and alleviating the interfacial instability caused by inconsistent volume changes during charging and discharging, thereby improving the energy density and rate performance of solid-state batteries. The binder ensures the structural integrity between the composite positive electrode material and the current collector, as well as between particles, while the sulfide coating shell acts as a bridge between the active material and the external environment, reducing the need for additional electrolytes or conductive agents in traditional solutions. Due to the tight bonding between the coating layer and the core, the tortuosity of the ion / electron transport path is significantly reduced, and the coating layer can effectively buffer volume expansion differences during charging and discharging, suppressing interfacial delamination.

[0043] In some embodiments of this application, the adhesive includes one or more of hydrogenated nitrile butadiene rubber (HNBR), nitrile butadiene rubber (NBR), ethyl cellulose (EC), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), alginate (ALG), hydrogenated styrene-butadiene block copolymer (SEBS), polyisobutylene (PIB), polyethylene-vinyl acetate (PEVA), and hydrogenated styrene-isoprene block copolymer (SEPS).

[0044] In some embodiments of this application, the mass percentage of the composite cathode material is 95-100%, for example, 95%, 96%, 97%, 98%, 99%, 100%, or any value between the two. By increasing the content of the composite cathode material in the cathode sheet to an extremely high proportion of 95% to 100%, the proportion of inactive components such as binders and conductive agents in the electrode layer is significantly reduced. Due to the reduction of inactive components, the contact between the composite cathode material particles is closer, reducing the transport resistance of ions and electrons at the inactive interface and optimizing the transport path. This optimization, combined with the sulfide coating characteristics inherent in the composite cathode material itself, can effectively improve the interfacial compatibility between the cathode active material and the solid electrolyte, reduce interfacial impedance, and provide efficient ion / electron transport channels. When this composite cathode material with excellent interfacial properties exists in the electrode layer in an extremely high proportion, its overall ion and electron transport efficiency is significantly improved, thereby effectively solving the problems of reduced energy density and increased transport resistance caused by excessive inactive components in traditional solid-state cathode composite electrode structures.

[0045] In some embodiments of this application, the density of the positive electrode layer on a single surface of the positive electrode sheet is 1-200 mg / cm³. 2 For example, 10 mg / cm 2 20 mg / cm 2 30 mg / cm 2 40 mg / cm 2 50 mg / cm 2 60 mg / cm 2 70 mg / cm 2 80 mg / cm 2 90 mg / cm 2 100 mg / cm 2 110 mg / cm 2 120 mg / cm 2 130 mg / cm 2 140 mg / cm 2 150 mg / cm 2 160 mg / cm 2 170 mg / cm 2 180 mg / cm 2 190 mg / cm 2 200 mg / cm 2 Or any value between any two.

[0046] In a fourth aspect of this application, a solid-state battery is provided, comprising the positive electrode sheet described in this application, a negative electrode sheet, and a solid electrolyte. By using the positive electrode sheet provided in this application, the internal interface of the positive electrode in the solid-state battery is significantly improved. The sulfide coating not only provides a fast ion / electron transport path and reduces interfacial impedance, but also buffers the stress caused by volume changes, reducing the increase in interfacial resistance. Therefore, without sacrificing energy density, the ion and electron transport efficiency of the solid-state battery is improved, and the rate performance is enhanced, effectively solving the problems of low energy density and poor rate performance in the prior art.

[0047] Solid-state electrolytes for solid-state batteries encompass various implementation schemes, including sulfide systems, oxide systems, and polymer systems. Sulfide all-solid-state electrolytes are a special type of solid-state electrolyte, whose main component is sulfide. These electrolytes are renowned for their excellent room-temperature ionic conductivity and good mechanical ductility, making them an ideal choice for achieving high-performance all-solid-state batteries. There are many types of sulfide all-solid-state electrolytes, including, for example, Li6PS5Cl (lithium thiophosphate chloride), Li... 10 GeP2S 12Crystalline sulfides such as (thiogermanium phosphide lithium sulfide) or sulfide glassy electrolytes can be used. These solid electrolyte materials can provide efficient ion transport channels and have a certain degree of flexibility, which helps to alleviate the volume change stress of electrode materials during charging and discharging. When used in conjunction with the positive electrode sheet of this application, they can further optimize the ion transport path, reduce interfacial impedance, buffer the stress caused by volume change, and reduce the increase in interfacial resistance.

[0048] This application does not impose any restrictions on the negative electrode sheet of solid-state batteries, which can be synthesized according to conventional processes in the field.

[0049] In a fifth aspect of this application, an electrical device is provided, including the secondary battery described in this application, the secondary battery providing electrical energy to the electrical device or serving as an energy storage unit for the electrical device.

[0050] The secondary battery provides electrical energy to electrical devices by converting stored chemical energy into electrical energy through a discharge process and supplying it to the devices to power their normal operation. For example, in electric vehicles, the secondary battery powers the drive motor; in portable electronic devices, the secondary battery directly supplies power to the internal circuitry.

[0051] The secondary battery, used as an energy storage unit in electrical equipment, refers to a battery that not only provides electrical energy but also acts as an energy buffer and storage medium. It can be charged when powered by an external power source and released when needed. For example, in smart grids or home energy storage systems, secondary batteries can be charged during off-peak electricity periods and discharged during peak periods, achieving peak shaving and valley filling, thus optimizing energy utilization. In hybrid vehicles, secondary batteries can recover and store braking energy, providing auxiliary power during acceleration and improving fuel efficiency.

[0052] The electrical equipment may include, but is not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0053] As can be seen from the above description in this application, the composite cathode material, cathode sheet, and solid-state battery provided in this application have the following technical effects: 1) Li a Ti b Ge c P x S y X zThe combination of high ionic conductivity and electrochemical activity for lithium-ion insertion and extraction breaks the conflict between the ratio of active material to ionic conductivity in the high-loading design of solid-state batteries, reduces the addition of heterogeneous phases in the electrode, and simultaneously increases the loading of active material and effective ionic conductivity in the electrode, thereby improving the energy density and rate capability of the battery. On the other hand, the cathode material and cathode electrode that integrate ionic conductivity and electrochemical active material can alleviate or even avoid the problem of increased interface resistance caused by different volume changes of multiple components during charging, thus improving the rate capability of solid-state batteries. 2) Li a Ti b Ge c P x S y X z High electronic conductivity can, on the one hand, completely avoid the addition of inactive conductive agents while ensuring the effective conductivity of the electrode, thereby increasing the proportion of active materials in the electrode and improving the battery energy density; on the other hand, it reduces the addition of heterogeneous conductive agents, thereby reducing interfacial impedance and improving rate performance; furthermore, it reduces electronic conductivity tortuosity and lowers the internal resistance of electronic transmission, which also improves rate performance. 3) Li a Ti b Ge c P x S y X z The zero-strain characteristic of the material, through the core-shell structure composite cathode, can slow down or even avoid the volume change during the charging and discharging process of the cathode, as well as the appearance of micro-gaps inside the cathode electrode, thereby reducing the interfacial resistance and improving the stability of the inner and outer interfaces of the electrode and the rate performance of the battery. In summary, using Li a Ti b Ge c P x S y X z A composite cathode material with a core-shell structure is formed with the positive electrode active material. Then, the composite cathode material and a binder are combined to form an integrated cathode sheet, utilizing Li... a Ti b Ge c P x S y X z It features high electronic conductivity, high ionic conductivity and high specific capacity, thus improving the problems of high proportion of inactive components leading to reduced energy density and multi-component composition leading to increased interface resistance and internal resistance and reduced rate performance in solid-state batteries.

[0054] In the comparative experiments provided in this application, unless otherwise specified, all experimental conditions and materials remain consistent to ensure comparability. Furthermore, all materials used in this application are commercially available.

[0055] The following provides a further description of a composite cathode material, its preparation method, cathode sheet, solid-state battery, and electrical device provided in this application.

[0056] Example 1: (1) Li 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Se 0.2 Preparation of LTGPSSe-1 (hereinafter referred to as LTGPSSe-1) Li₂S, P₂S₅, TiS₂, GeS₂, and TiSe₂ in a molar ratio of 35:45:68:30:12 were ball-milled at 600 rpm for 60 h at room temperature in an argon-sealed environment. Then, they were mixed with S in a molar ratio of 4 and annealed at 800 °C for 8 h. The resulting substance was LTGPSSe₁, and its SEM image is shown below. Figure 1 TEM image Figure 2 ; (2) Preparation of composite cathode materials LFP and LTGPSSe-1 (mass ratio of 99%:1%) were ball-milled and then calcined (temperature 300℃ time 3h) to form a core-shell material, wherein the core is LFP and the shell is a layer of sulfide LTGPSSe-1; (3) Preparation of positive electrode layer The prepared composite cathode material and binder (mass ratio 98%:2%) were mixed using a dry process and coated onto carbon-coated aluminum foil, with a single-sided surface density of 35 mg / cm². 2 It is pressed into electrode sheets; (4) Preparation of negative electrode layer The silicon anode and binder are added to a solvent and mixed thoroughly to produce a product with a solid content of 10%. 60% of the negative electrode slurry is coated onto carbon-coated copper foil, dried, and rolled into a negative electrode layer. (5) Preparation of electrolyte layer The sulfide solid electrolyte and binder are added to the solvent and mixed evenly to prepare a product with a solid content of 30%. 80% electrolyte slurry is coated onto light aluminum foil and dried to form an electrolyte film; (6) Fabrication of monolithic all-solid-state batteries The electrolyte membrane is transferred onto the negative electrode by isostatic pressing. Then, a single double-layer positive electrode layer, two single-layer negative electrode layers, and two electrolyte membranes are isostatically pressed to form a stacked structure of negative electrode + electrolyte + positive electrode + electrolyte + negative electrode. Finally, the tabs are welded and the cells are encapsulated with an aluminum-plastic film to form a single solid-state battery.

[0057] Example 2: Prepared using the same process as in Example 1, with the difference being: LFP and LTGPSSe-1 (mass ratio 98%:2.0%) are ball-milled and then calcined to form a core-shell material, wherein the core is LFP and the shell is sulfide LTGPSSe-1.

[0058] Example 3: Prepared using the same process as in Example 1, with the difference being: LFP and LTGPSSe-1 (mass ratio 97%:3%) are ball-milled and then calcined to form a core-shell material, wherein the core is LFP and the shell is sulfide LTGPSSe-1.

[0059] Example 4: Prepared using the same process as in Example 1, with the difference being: The prepared positive electrode material and binder (mass ratio 97%:3%) were mixed using a dry process and coated onto carbon-coated aluminum foil, with a single-sided surface density of 35 mg / cm². 2 It is pressed into an electrode sheet.

[0060] Example 5: Prepared using the same process as in Example 1, with the difference being: The prepared positive electrode material and binder (mass ratio 96%:4%) were mixed using a dry process and coated onto carbon-coated aluminum foil, with a single-sided surface density of 35 mg / cm². 2 It is pressed into an electrode sheet.

[0061] Example 6: Prepared using the same process as in Example 1, with the difference being: Li₂S, P₂S₅, TiS₂, GeS₂, and TiTe₂ in a molar ratio of 35:45:68:30:12 were ball-milled at 600 rpm for 60 h at room temperature in an argon-sealed environment. Then, they were mixed with excess S and annealed at 800 °C for 8 h. The resulting substance was LTGPSTe⁻¹, with the molecular formula Li₂. 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Te 0.2 3.

[0062] Example 7: Prepared using the same process as in Example 1, with the difference being: Li₂S, P₂S₅, TiS₂, GeS₂, and TiSe₂ in a molar ratio of 35:42:68:36:12 were ball-milled at 600 rpm for 60 h at room temperature in an argon-sealed environment. Then, they were mixed with a small amount of S in a molar ratio of 3 and annealed at 800 °C for 8 h. The resulting substance was LTGPSSe₂ with the molecular formula Li. 1.75 Ti2(Ge 0.3 P 0.7 S 3.8 Se 0.2 3.

[0063] Comparative Example 1: Prepared using the same process as in Example 1, with the difference being: LFP is directly formed into cathode material by ball milling and calcination. Comparative Example 2: Prepared using the same process as in Example 1, with the difference being: LFP and LiTi2(PS4)3 (hereinafter referred to as LTPS, conventional sulfide electrolyte) (mass ratio of 99%:1%) were ball-milled and then calcined to form a core-shell material, wherein the core is LFP and the shell is sulfide LTPS.

[0064] Comparative Example 3: Prepared using the same process as in Example 1, with the difference being: LFP, Li 10 GeP2S 12 (Hereinafter referred to as LGPS, conventional sulfide electrolyte) (mass ratio of 99%:1%) is formed into a core-shell material by ball milling and calcination, wherein the core is LFP and the shell is sulfide LGPS.

[0065] Experimental example: The ionic and electronic conductivity of the powder materials were measured using the ZENNIUM X measurement system. The solid-state batteries prepared in the above examples and comparative examples were tested on the Ruineng ACTS battery testing system at room temperature under constant current and constant voltage charging at 0.1C with a cutoff current of 0.05C. They were then discharged at constant currents of 0.1C, 0.33C, 0.5C, 1C, and 2C, respectively, with voltage ranges from 2.0 to 3.65V. The results are shown in Tables 1 and 2 below. Table 1

[0066] As shown in Table 1, under the premise of consistent sulfide coating, the positive electrode active material and sulfide in Examples 1-5 have high reversible capacity and energy density at a ratio of 97%:3%-99%:1%, with the 97%:3% ratio in Example 3 being the best. Compared to Example 6, Example 1 shows that X selected from Se has higher reversible capacity and energy density than that selected from Te; in Example 7, X is selected from sulfides of Se with different atomic ratios, and the reversible capacity and energy density are basically the same.

[0067] All embodiments showed significant improvements compared to comparative examples using conventional sulfide coating and uncoated formulations.

[0068] Table 2

[0069] As shown in Table 2, the rate performance of each embodiment is significantly improved compared to the comparative examples using conventional sulfide coating and uncoated materials; in each embodiment, the overall rate performance of Se selected as the X element is better.

[0070] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A composite cathode material, characterized in that, It includes a core and a coating shell, wherein the core comprises a positive electrode active material, and the coating shell comprises one or more sulfides with the molecular formula Li. a Ti b Ge c P x S y X z , 0<a≤4, 0≤b≤4, 0≤c≤3, 0≤x≤3, x+c=3; 0≤y≤12, 0≤z≤12, y+z=12; X is selected from at least one of Te, Se, and O.

2. The composite cathode material according to claim 1, characterized in that, The mass ratio of the positive electrode active material to the sulfide is 80:20-99.95:0.

05.

3. The composite cathode material according to claim 2, characterized in that, The mass ratio of the positive electrode active material to the sulfide is 90:10-99.5:0.

5.

4. The composite cathode material according to claim 3, characterized in that, The mass ratio of the positive electrode active material to the sulfide is 97:3-99:

1.

5. The composite cathode material according to any one of claims 1-4, characterized in that, The positive electrode active material includes lithium iron phosphate; lithium iron manganese phosphate; lithium-rich manganese-based active material; LiCoO2; LiNiO2; LiMnO2; Li2MnO3; LiMn2O4; LiNi a Co b Mn c O2, where 0 < a < 1, 0 < b < 1, 0 < c < 1, and a + b + c = 1; LiNi 1-y Co y O2, where 0 < y < 1; LiCo 1-y Mn y O2, where 0 < y < 1; LiNi 1-y Mn y O2, where 0 < y < 1; LiNi a Co b Mn c O4, 0 < a < 2, 0 < b < 2, 0 < c < 2, and a + b + c = 2; LiMn 2- z Ni z O4(0 < z < 2); LiMn 2-z Co z O4, where 0 < z < 2; LiNi x Al y Co z O2, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1; sodium-based layered oxide; sodium-based Prussian blue; sodium-based polyanion and one or more combinations of their modified dopants.

6. The composite cathode material according to claim 1, characterized in that, The sulfide has the molecular formula Li. 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Se 0.2 3. Li 1.75 Ti2(Ge 0.3 P 0.7 S 3.8 Se 0.2 3. Li 1.75 Ti2(Ge 0.25 P 0.75 S 3.8 Te 0.2 One or more of 3.

7. The composite cathode material according to claim 1, characterized in that, The number of layers of the outer shell is 1-10.

8. A method for preparing the composite cathode material as described in any one of claims 1-7, characterized in that, include: Raw materials containing Li, Ti, Ge, P, S, and X were thoroughly mixed in a protective gas atmosphere according to atomic ratios. Then, supplementary S was added, and the mixture was annealed at 300-800℃ for 4-12 hours to obtain a product with the molecular formula Li. a Ti b Ge c P x S y X z sulfides; The positive electrode active material is thoroughly mixed with the sulfide and then calcined at 100-350℃ for 0.5-3 hours to obtain the composite positive electrode material.

9. The preparation method according to claim 8, characterized in that, The raw materials containing Li, Ti, Ge, P, S, and X include one or more of S, Li2S, P2S5, TiS2, GeS2, and TiX2.

10. A positive electrode plate, characterized in that, It includes a current collector and a positive electrode layer disposed on at least one surface of the current collector; the positive electrode layer includes the composite positive electrode material and binder as described in any one of claims 1-7.

11. The positive electrode sheet according to claim 10, characterized in that, The composite cathode material has a mass percentage of 95-100%.

12. A solid-state battery, characterized in that, It includes the positive electrode sheet as described in claim 10 or 11, as well as the negative electrode sheet and the solid electrolyte.

13. An electrical appliance, characterized in that, Includes the solid-state battery of claim 12, wherein the solid-state battery provides electrical energy to the electrical device or serves as an energy storage unit for the electrical device.

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